backend/tests/unit/test_cloning.py

import pytest
from fastapi.testclient import TestClient
from unittest.mock import MagicMock
from app.main import app
from app.services.clone_service import CloneService, get_clone_service

class TestVoiceCloning:
    
    @pytest.fixture
    def mock_clone_service(self):
        mock = MagicMock(spec=CloneService)
        # Setup specific return values
        mock.get_supported_languages.return_value = ["en", "es"]
        mock.clone_voice.return_value = "dummy_path.wav"
        return mock
        
    @pytest.fixture
    def client(self, mock_clone_service):
        # Override dependency
        app.dependency_overrides[get_clone_service] = lambda: mock_clone_service
        with TestClient(app) as c:
            yield c
        # Cleanup
        app.dependency_overrides.clear()

    def test_synthesize_endpoint(self, client, mock_clone_service, tmp_path):
        """Test /clone/synthesize with mocked service"""
        
        # Define side effect to create the file when called
        def create_dummy_output(*args, **kwargs):
            output_path = kwargs.get("output_path")
            if output_path:
                with open(output_path, "wb") as f:
                    f.write(b"fake audio data")
            return output_path

        mock_clone_service.clone_voice.side_effect = create_dummy_output

        # Mock input file
        dummy_wav = tmp_path / "ref.wav"
        dummy_wav.write_bytes(b"dummy ref audio")

        with open(dummy_wav, "rb") as f:
            response = client.post(
                "/api/v1/clone/synthesize",
                data={"text": "Hello", "language": "en"},
                files={"files": ("ref.wav", f, "audio/wav")}
            )
            
        assert response.status_code == 200
        assert mock_clone_service.clone_voice.called
        assert response.content == b"fake audio data"

    def test_synthesize_no_files(self, client):
        """Test validation error when no files provided"""
        response = client.post(
            "/api/v1/clone/synthesize",
            data={"text": "Hello"},
            files=[] # Empty
        )
        assert response.status_code in [400, 422]

    def test_languages_endpoint(self, client, mock_clone_service):
        """Test /clone/languages"""
        response = client.get("/api/v1/clone/languages")
        
        assert response.status_code == 200
        assert response.json() == {"languages": ["en", "es"]}